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dlinn [17]
3 years ago
8

A device contains two circuits. The second circuit is a backup for the first, so the second is used only when the first has fail

ed. The device fails when and only when the second circuit fails. Let X and Y be the times (in years) at which the first and second circuits fail, respectively. Their joint probability density function (pdf) is 6e-xe-20 for 0 < x < y 〈 oo; otherwise (a) Find the pdf of X. Identify the distribution of X (b) Find the pdf of Y (c) What is the expected time at which the device fails?

Mathematics
1 answer:
Wittaler [7]3 years ago
5 0

Answer:

Step-by-step explanation:

The pdf of X is given by 3e^x(1-e^-2y). Please check the screenshot for the workings.

The pdf of Y is given by 6e^-2y. Please check the screenshot for the workings.

The expected time the device fails is the expected time Y fails, so we are going to find the expected time of Y which equals to 0.83.

Please check the screenshop for the workings. Thanks

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Olin [163]
7. honestly not 100% sure. i did 364 divided by 13 which was 28 so 28 flowers per table. and then 28 divided by 4. 7 flowers per vase.
8 0
2 years ago
4 question in one 65 points
jeka94

Q6.

The slope-intercept form: y = mx + b

m - slope

b - y-intercept

We have: slope m = 3, y-intercept (0, 4) → b= 4

<h3>Answer: y = 3x + 4</h3>

Q7.

2x + 4y = 4     |subtract 2x from both sides

4y = -2x + 4     |divide both sides by 4

y = -0.5x + 1

Only second graph has y-intercept = 1.

<h3>Answer: The second graph.</h3>

Q8.

The point-slope form:

y-y_1=m(x-x_1)\\\\m=\dfrac{y_2-y_1}{x_2-x_1}

We have

(-16,\ 8)\to x_1=-16,\ y_1=8\\(4,\ -2)\to x_2=4,\ y_2=-2

Substitute:

m=\dfrac{-2-8}{4-(-16)}=\dfrac{-10}{20}=-\dfrac{1}{2}\\\\y-8=-\dfrac{1}{2}(x-(-16))\\\\y-8=-\dfrac{1}{2}(x+16)

<h3>Answer: The first equation.</h3>

Q9.

It's a vertical line. The equation of a vertical line is x = <em>a</em>, where <em>a</em> is any real number.

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6 0
3 years ago
Read 2 more answers
leo knows that each time a digit moves one place to the left in a whole number the value of the digit is 10 times as much. descr
Serga [27]

Answer:

Leo is true for any numbers (including decimal numbers)

Step-by-step explanation:

* Lets explain how to solve the problem

- In number 256

# 6 is the unit digit (one digit)

# 5 is the ten digit (10 digit)

# 2 is the hundred digit (100 digit)

- If we change the number to 2563

# 6 digit is moved 1 place to the left now its place changed from unit

  digit to ten digit (from 1 to 10) that means 6 in the second number

  is 10 times the 6 in the first number

# 5 digit is moved 1 place to the left now its place changed from ten

  digit to hundred digit (from 10 to 100) that means 5 in the second

  number is 10 times the 5 in the first number

# 2 digit is moved 1 place to the left now its place changed from  

  hundred digit to thousand digit (from 100 to 1000) that means 2

  in the second number is 10 times the 2 in the first number

- In number 2.345

# 2 is the unit digit (one digit)

# 3 is the tenth digit (1/10 digit)

# 4 is the hundredth digit (1/100 digit)

# 5 is the thousandth digit (1/1000 digit)

- If we change the number to 23.45

# 3 digit is moved 1 place to the left now its place changed from tenth

  digit to unit digit (from 1/10 to 1) that means 3 in the second number

  is 10 times the 3 in the first number

# 4 digit is moved 1 place to the left now its place changed from  

  hundredth digit to tenth digit (from 1/100 to 1/10) that means 4 in the

  second number is 10 times the 5 in the first number

# 5 digit is moved 1 place to the left now its place changed from  

  thousandth digit to hundredth digit (from 1/1000 to 1/100) that means

  5 in the second number is 10 times the 5 in the first number

∴ Leo is true for any numbers (including decimal numbers)

3 0
3 years ago
A dog is leashed to the corner of a house. How much running area does the dog have? Round answer to the nearest square foot, if
sashaice [31]

Answer:

  942 ft²

Step-by-step explanation:

The diagram shows the area to be 3/4 of that of a circle of radius 20 ft. The area of a circle is given by ...

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Then 3/4 of that area is ...

  dog run = (3/4)(400π ft²) = 300π ft² ≈ 942.48 ft²

The area of the dog's run is about 942 ft².

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3 years ago
Audryn left a $12 tip on a $68.73 restaurant bill. What percent tip did she leave? Round to the nearest tenth of a percent.
Fiesta28 [93]
So, if we take 68.73 to be the 100%, what is 12 in percentage off of it?

\bf \begin{array}{ccll}&#10;amount&\%\\&#10;\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\&#10;68.73&100\\&#10;12&p&#10;\end{array}\implies \cfrac{68.73}{12}=\cfrac{100}{p}\implies p=\cfrac{12\cdot 100}{68.73}

seems Audryn is being generous, she probably got the silverware and the maple leaves tablecloth.
4 0
3 years ago
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